This invention relates in general to the propagation of signal energy within solid material, such as detonation waves conducted through bulk explosives, and the effect thereon of shock waves propagated more rapidly through the bulk material.
The invention is more particularly applicable to solid explosives wherein shock waves are generated in longitudinal cavities or channels formed in the explosive material. Propagation of the shock waves at velocities higher than the detonation waves in the channels and the resulting increase in detonation velocity is known as the "channel effect", which is modified in accordance with the present invention.
In connection with explosives, it is already well known that propagation of self-sustaining detonation waves at a prescribed wave velocity is responsible for rapid consumption of the explosive material. Such self-sustained detonation waves are furthermore known to increase in velocity with the density of the explosive material through which the detonation wave is propagated.
It is also known in the art that the detonation wave velocity in a tubular or hollow type explosive is higher than that in a solid body explosive. The increase in magnitude of the detonation wave velocity beyond its otherwise established limits is caused by a shock wave generated in the channel of the tubular explosive, the shock wave being propagated through the channel passage at a velocity higher than that of the detonation wave in the annular portion of the explosive in surrounding relation to the channel. Such higher velocity shock wave in the channel compresses the solid particles of the explosive material, within the annular portion of the explosive body forwardly of the detonation wave, to locally increase explosive density with a corresponding increase in the self-sustained detonation wave velocity. The resulting detonation velocity approaches that of the explosive powder when fully compressed to crystal density. Such increase in the detonation velocity resulting from what is known as the "channel effect", is less for explosive charges of higher original density.
It is also known that the effective detonation wave velocity may be further increased beyond what is possible as a result of the aforementioned "channel effect", by periodic blockage of shock wave propagation through the channel passage by means of bulk material disposed between adjacent axial ends of a plurality of axially aligned cavities in a multiple-cavity type of tubular explosive. In such a multiple-cavity arrangement, reflection of the shock wave at the end of each cavity initiates the explosive material thereat to generate two new detonation waves respectively propagated forwardly and rearwardly while a new shock wave is generated in the following cavity after some delay. When the detonation wave propagating forwardly collides with the rearwardly directed detonation wave generated at the end of the cavity, pressure oscillations not present in continuous, open channel type cavity arrangements are produced. Nevertheless, the rate of explosive consumption is increased, corresponding to an increase in the average detonation wave velocity.
It is an important object of the present invention to provide a continuous open channel type of cavity arrangement in a solid explosive capable of increasing detonation to an ultra-high wave velocity greater than the increase in velocity heretofore achieved by periodic blockage of shock waves within multiple-cavity arrangements, and without the previous oscillations associated therewith.
In accordance with the foregoing object, it is a further object to exploit the ultra-high velocity effect to increase jet velocity in shaped charges, reduce the angle between detonation front and liner in such shaped charges and control wave profile in plane wave lenses.